In the art, a number of adjustable seat constructions exist which makes it possible to adjust the backrest in relation to the seat, the height of the backrest in relation to the level of the seating surface, and in some instances also the width of the seat and/or backrest in relation to the user.
A number of these prior art chair constructions only makes it possible to adjust one or a few of the features of the chair construction. For people of normal built, this is usually not a problem, but especially for handicapped users there is a need to be able to adjust the chair perfectly in order to provide the most comfortable seating position for the user. This even more so as handicapped persons often will be forced to spend longer periods of time in a chair than normal persons, who can leave the chair for a while and then return.
Especially for chair constructions in wheelchairs suitable for persons having handicaps which necessitate the provision of further supports such as leg supports on the sides as well as back supports, chest supports, shoulder supports and the like, the requirements relating to the adjustability of the chair construction are greatly increased. Usually, this has been addressed in the art by providing one-off special constructions, especially suited for the user in question. This in turn is a very costly and resource-demanding process. In particular, when the one-off construction is made for children, a further problem arises as the child grows, in that the one-off especially produced chair for the child at one size will, as the child grows, become more and more of a compromise, and at a certain time it is necessary to have a further chair built in order to address the needs of the child having outgrown the original chair.
An additional problem especially relating to chair constructions for the handicapped is that they usually have one or more extra supports mounted, for example on the backrest, in order to provide relief for the user during use. By reclining the backrest in relation to the seat in a traditional wheelchair, or in chair constructions as for example suggested in NL 7115696, the additional supports arranged either on the backrest or the seat construction are displaced due to the fact that the pivot point of the backrest in relation to the seat does not follow the actual movement of the back in relation to the seat of the user.
Consequently, there is a need for providing an adjustable chair construction which alleviates at least the problems described above.